572 research outputs found
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Ant-pollination: A Rare and Enigmatic Mutualism
No full textMutualism refers to interactions between species that
result in reciprocal benefits. There are several mutualistic interactions between plants and animals. These mutualisms are in the form of a biological barter in which the resources of one species are exchanged with the services of the other. Mutual interactions are common
between plants and ants (Beattie, 1985; Rico-Gray and
Oliveira, 2007). Myrmecophily, particularly in species
of Acacia, is one such mutualism in which plants possess
structural adaptations that provide ants with food and/or
shelter. In exchange, ants protect plants from herbivores. Ants also act as seed dispersal agents. Many plant species produce fruits or seeds with special ant attractants – arils or elaiosomes. Ants carry such fruits and seeds to their nest. After consuming the attractants, the seeds/fruits are discarded with other wastes either in the nest or outside the nest entrance
Is There Enough Science for Conservation Action?
No full textWe argue that there is not enough science to appropriately support many of the conservation measures currently being proposed, and hence, we cannot be sure of the objectivity of the conservation actions being implemented. The objectivity claimed to be underlying conservation actions is more assumed than real. We also suggest that the approach to conservation is driven more by moral commitments than by tested concepts, and it is further biased by our anthropocentric evaluation of ecological processes and their outcomes. Conservation science is a young subject, which needs to be nourished while it continues to feed on its roots-ecology and evolutionary biology
Sustaining biodiversity conservation in human-modified landscapes in the Western Ghats: Remnant forests matter
No full textHuman-modified tropical landscapes under semi-natural or agro-ecosystems often harbor biodiversity of
significant conservation value. In the Western Ghats of India, these ecosystems also provide connectivity
between protected areas and other remnant forests. We investigated the conservation value of these
landscapes and agro-ecosystems using results from 35 studies covering 14 taxonomic groups. Large, conspicuous
taxonomic groups and tree-covered land-use types have received much focus in this area of
research in the Western Ghats. We computed a response ratio defined as the log ratio of species richness
in human land use to species richness in forest control site from 17 studies. In a meta-analysis, we investigated
variation of this ratio across studies with respect to three variables: taxonomic group, the landuse
type sampled and the extent of forest cover within the study landscape. Higher forest cover within
the landscape emerged as a major positive influence on biodiversity in human-modified landscapes for
vertebrates and vegetation while no patterns emerged for invertebrates. Our results suggest that loss
of remnant forest patches from these landscapes is likely to reduce biodiversity within agro-ecosystems
and exacerbate overall biodiversity loss across the Western Ghats. Conservation of these remnant forest
patches through protection and restoration of habitat and connectivity to larger forest patches needs to
be prioritized. In the densely populated Western Ghats, this can only be achieved by building partnerships
with local land owners and stakeholders through innovative land-use policy and incentive schemes
for conservatio
Beyond parks as monoliths: Spatially differentiating park-people relationships in the Tadoba Andhari Tiger Reserve in India
No full textParks represent spatially and socially heterogeneous conservation units, yet are often assessed and managed
using spatially homogeneous approaches. This paper represents an effort to focus on the larger
social–ecological landscapes within which protected areas are embedded, to understand why conservation
succeeds and fails in different parts of the landscape. In a wildlife sanctuary in the central plains of
India (Tadoba Andhari Tiger Reserve), we address: (i) how people living within and immediately outside a
park differentially impact its resources and (ii) how the park differentially impacts communities living
within. Using forest plots, satellite imagery and interviews, we evaluate park conservation by assessing
plant diversity, land cover change, forest fragmentation, and attitudes of local communities towards conservation.
We find that interior villages have a negative impact on regeneration, but there is a decline in
tree species diversity, and increased forest cover change and fragmentation at the park periphery. Interior
villages suffer greatly from crop and livestock depredations by wildlife and consider park rules to be
unfairly devised. Yet, they affirm the importance of the park for conservation, and are willing to work
with park authorities for stricter protection. Park authorities largely focus on resettlement of interior villages,
when they should also pay attention to protecting the peripheral areas of the park from severe degradation
by surrounding villages. In summary, we find that different parts of the park landscape face
different conservation challenges. Taking into account spatial variations in the factors influencing conservation
can greatly benefit the management of protected areas
Street trees in Bangalore: Density , diversity, composition and distribution
No full textOnce renowned as India’s ‘‘gardencity’’, the fast growing southern Indian city of Bangalore is rapidly losing tree cover in public spaces including on roads. This study aims to study the distribution of street trees in Bangalore, to assess differences in tree density ,size and species composition across roads of different widths, and to investigate changes in planting practices overtime. A spatially stratified approach was used for sampling with 152transects of200m length distributed across wide roads
(with awidthof24morgreater),mediumsizedroads(12–24m) and narrow roads(lessthan12m).
We find thedensityofstreettrees inBangaloretobe lower thanmany otherAsiancities.Species diversity is high ,withthemostdominantspeciesaccountingforlessthan10%oftheoverallpopulation.
Narrowroads,usuallyincongestedresidentialneighborhoods,havefewertrees,smallersizedtree
species,andalowerspeciesdiversitycomparedtowideroads.Sincewideroadsarebeingfelledoftrees
acrossthecityforroadwidening,thisimpliesthatBangalore’sstreettreepopulationisbeingselectively
denudedofitslargesttrees.Oldertreeshaveamorediversedistributionwithseverallargesized
species,whileyoungtreescomefromalessdiversespeciesset,largelydominatedbysmallstatured
specieswithnarrowcanopies,whichhavealowercapacitytoabsorbatmosphericpollutants,mitigate
urban heatislandeffects,stabilizesoil,preventgroundwaterrunoff,andsequestercarbon. This has
serious implications for the city’s environmental and ecological health.These results highlighttheneed
to protect large street trees on wide roads from treefelling, and to select an appropriate anddiversemix
of largeandsmallsizedtreespeciesfornewplanting
Floral resources, pollinators and fruiting in a threatened tropical deciduous tree
No full textNothapodytes nimmoniana (Family Icacinaceae) is a deciduous tree species distributed in Asia facing severe population decline. Wood chips from the tree are a source of camptothecin, a globally soughtafter alkaloid with cancer-treating properties, and are harvested unsustainably in natural forests. We studied the pollination ecology of the species and asked if there are constraints in pollination and fruiting success in its natural populations.We also discuss the potential
effects of wood extraction on pollinators and reproductive success in the population
Reforestation: Conclusions and Implications
No full textThis hook was written with two major objectives in mind. Our primary goal was to evaluate the drivers and processes associated with reforesting landscapes across a range of contexts and continents, to determine factors which appear to be specific to certain situations, and others which seem to be common across multiple contexts. Since reforestation is an area of study that crosses ecological, biophysical and social boundaries, our second objective was to develop interdisciplinary frameworks that link methods and approaches from different areas of science, to study the patterns and processes associated with reforesting landscapes. We evaluate the major findings of this volume based on these two objectives. First, we compare the research findings from different chapters, to help us discern the common designs and the unique threads that create a variety of reforestation patterns across landscapes (Table 16.1). We then use a combination of FA0 data along with the specific case studies presented here for different countries, and develop a typology of forest change (Table 16.2). Finally, the main techniques and
approaches used within each research study are presented, and assessed in terms of their effectiveness for reforestation research (Table 16.3). We conclude with an
assessment of the implications of these findings, and outline some challenges for future research on reforestation
Invasive Plants in Tropical Human-Dominated Landscapes: Need for an Inclusive Management Strategy
No full textThis chapter argues that solutions to the management of invasive species need to be reworked to take into account the fact that invasive species can impact human livelihoods both negatively and positively. Besides the existing strategies for the management of invasive species, there is a need for alternative strategies in terms of the net benefit they yield, taking of course all benefits and costs into account. A specific case of control of invasive species in largely tropical landscapes is considered, with the attendant problems of human dependence on natural resources as well as lack of investment portfolios to control invasive species. Management strategies are proposed that promote use of the invasive as a way of minimizing the net costs of the invasive species
Rights, Governance, and Conservation of Biological Diversity
No full textLosses of biological diversity, or diversity of life at all
levels of biological organization, have crossed a boundary
beyond which they pose serious consequences for humanity (Rockstrom et al. 2009). Despite enormous effort by state and global actors to arrest declines in biological diversity, rates of deforestation in the tropics
remain high (Asner et al. 2009). Centralized state control
of forests and other ecosystems, in the form of national
parks and other protected areas, has been a dominant
conservation paradigm, and it has been fueled by neoliberal
approaches in international conservation (Brockington
et al. 2008). The protected-area approach has often resulted in adverse effects on the livelihoods of local people (Saberwal et al. 2001; Adams & Hutton 2007). Due
to the high spatial correlation between poverty and high
levels of biological diversity (Sachs et al. 2009), attempts have been made to link conservation of biological diversity with livelihoods and poverty alleviation (Adams et al.2004). Such efforts have had limited success due to a
lack of understanding of the linkages between poverty
and conservation and the absence of state support for
alternative approaches (Agrawal & Redford 2006; Lele
et al. 2010). Conservation projects in which increasing
income is assumed to decrease dependence on resources
(Brechin et al. 2002) treat poverty too simply (Sen 1999).
We propose that the process of conservation be reenvisioned
to include political empowerment to people,restitution of rights and human dignity, and building of local institutions. A human-rights-based approach increases
the role of local communities in conservation and the potential for democratic governance of natural resources. Using India as an example, we offer suggestions for developing decentralized mechanisms to restorerights to local communities. Our suggestions are applicable
to much of the developing world, where poverty
and centralized management of protected areas have not
curtailed losses of biological diversity and have alienated
local communities (Sodhi et al. 2006). We do not
assume that rights-based approaches will mitigate loss
of biological diversity, but suggest that efforts based
on local knowledge, institutions, and practices will empower local communities to better manage biological
diversity
Landscape-level effects on avifauna within tropical agriculture in the Western Ghats: Insights for management and conservation
No full textA critical handicap to tropical biodiversity conservation efforts in agroecosystems is the unknowns
regarding the influence of landscape-scale factors on the persistence of species. To address these uncertainties,
we explored two essential landscape-scale questions, within India’s biologically-rich Western
Ghats, examining two nearby human-dominated landscapes that dramatically differed in their pattern
of land cover. First, how does the proximity of intact forest patches affect bird community composition
within agricultural landscapes? Second, can simple remote sensing-derived measures (brightness, wetness,
and NDVI) be used to estimate native bird species composition within those landscapes? In both
landscapes, as distance to intact forest decreased, the similarity in bird community composition between
agricultural areas and intact forest increased. This suggests that the retention of tropical forest bird communities
within human-dominated landscapes critically depends on the maintenance of nearby intact
forest. In an answer to the second question, the remote sensing measures correlated with forest-affiliated
avian species richness in only one of the two landscapes, reflecting an ecological difference between the
two in the response of forest bird species to local agricultural conditions. In the landscape where a correlation
was found, there was high variation in vegetative structure, which strongly impacted both the
remote sensing measures and forest bird species richness. In the other landscape, forest species richness
strongly correlated with changes in tree species composition in the agriculture, a factor that could not be
detected by the remote sensing metrics. In order to successfully conserve biodiversity in tropical agricultural
landscapes, our findings show that it is essential to conserve intact forest within those landscapes
and to understand the effect of local agricultural practices on species